Directory Structure
The directory structure itself is determined by the keyword conventions, while the location of a given file within the CALDB is determined by its header keyword values. The CALDB directory structure is given in Table 1, which may be used to locate a specific file in your local CALDB.
| TELESCOP | INSTRUME | INDEX/CCLS | CCNM | ||
| $CALDB/data/chandra/ | acis/ | index/ | (ACIS index files) | ||
| bcf/ | badpix, evtsplt, gain, gtilim, grade, qe | ||||
| cpf/ | 2dpsf, fefs, osip | ||||
| ephin/ | index/ | (EPHIN index files) | |||
| bcf/ | geom | ||||
| hrc/ | index/ | (HRC index files) | |||
| bcf/ | badpix, degap, fptest, eftest, gtilim, sattest, tapring, qe | ||||
| cpf/ | 2dpsf | ||||
| pcad/ | index/ | (PCAD index files) | |||
| bcf/ | align, badpix, ccd, cti, fdc, image, iru, rws, sfma | ||||
| sim/ | index/ | (SIM index files) | |||
| bcf/ | pos, poscorr | ||||
| tel/ | index/ | (TEL index files) | |||
| bcf/ | aimpts, geom, sky, tdet, obitol | ||||
|
DETNAM
(INSTRUME="TEL") |
CCLS
(GRATING="NONE") |
CCNM | |||
| hrma/ | bcf/ | effarea, vignet | |||
| cpf/ | rpsf, wpsf | ||||
| GRATING | CCLS | CCNM | |||
| grating/ | hetg/ | bcf/ | greff | ||
| cpf/ | arf, rmf | ||||
| letg/ | bcf/ | greff | |||
| cpf/ | arf, rmf |
The structure under the "tel" branch is dictated by the guidelines in the ASC FITS Designer's Guide (PS, 40pp). The GRATING keyword and a corresponding classification keyword in the index file are both required.

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